Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the burden of behavioral disclosure. It states 'Pure' (no side effects) and 'price 0.0 (free)' (cost), and 'from built-in tables' (no external data). These are useful behavioral traits beyond the schema. However, it does not mention error cases, return format, or rate interpretation details, which keeps it from a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.